1. Field of the Invention
This invention relates in general to conveyor systems and more particularly to plastic wheel assemblies for use with overhead conveyor systems.
2. Description of the Prior Art
Overhead conveyor systems are well known in the prior art. Such systems are commonly utilized in manufacturing and fabrication plants and in food processing plants. Generally these systems incorporate an overhead beam or pipe and multiple wheeled conveyor units which run along the beam or pipe. Individual conveyor units are generally coupled utilizing a steel chain or other similar methods. Chain drives or other drive mechanisms are then utilized to move the conveyor units around the system.
Known overhead conveyor systems typically utilize metal conveyor wheels which are supported by ball bearings. Such wheels are subject to rust and the ball bearings utilized must be continually lubricated. A concomitant problem in food processing applications is the continued possibility of lubricant contamination of the food product being processed by the plant.
In addition to the rust and lubrication problems noted above, metal conveyor systems are generally quite noisy and may be subject to corrosion in areas where corrosive chemical vapors are present. In view of the above, several systems have been proposed recently which utilize plastic conveyor wheels and components. While an improvement over known metallic conveyor wheel systems, plastic wheel systems are subject to additional problems.
The incorporation of plastic conveyor wheels brings about additional problems which must be addressed. Typically these plastic wheels require a metallic ferrule or rim which must be pressed into the plastic wheel to support rotation on a metal shaft. This complicates the manufacturing of such wheels and is an area where breakdown or failure may occur. A second problem associated with both plastic and metallic wheels is the difficulty encountered in replacing an individual wheel. Generally, an entire conveyor unit must be disassembled to remove a single wheel. This is necessary due to the inability of a repair technician to secure the inner end of the axle through a wheel in order to remove the fastening device utilized.
Thus, it should be apparent that a need exists for an improved overhead conveyor system which may be easily and simply repaired and maintained.